Semiconductor device using semiconductor chip

ABSTRACT

A semiconductor device includes an insulating substrate  2  having an obverse surface formed with a die pad  3 , a rectangular semiconductor chip  7  such as an LED chip bonded to the die pad with a die bonding material  10 , and a molded portion  9  made of a synthetic resin for packaging the semiconductor chip. The die pad  3  may be rectangular with dimensions close to those of the semiconductor chip or circular with a diameter close to the diagonal dimension of the semiconductor chip, whereby the positioning and orienting of the semiconductor chip can be accurately performed in bonding the semiconductor chip.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device using asemiconductor chip, and particularly to a semiconductor device includinga semiconductor chip bonded to a die pad and packaged with a moldedportion made of a synthetic resin.

2. Description of the Related Arts

Generally, a light emitting diode lamp of the type described aboveincludes an insulating substrate in the form of a chip, on which a diepad and a pair of first and second electrode terminals all of which aremade of a metal film are formed so that the die pad is electricallyconnected to the first electrode terminal. The device further includes asemiconductor chip bonded to the die pad and electrically connected tothe second electrode terminal.

To bond the semiconductor chip to the die pad electrically connected tothe first electrode terminal in the semiconductor device, a thermallymeltable die bonding material such as solder paste is used.Specifically, an appropriate amount of such die bonding material isapplied to an upper surface of the die pad, and then the semiconductorchip is placed on the die bonding material. In this state, the diebonding material is once melted by heating and then hardened.

Conventionally, although the die pad has a rectangular configurationwhich is similar to the rectangular configuration of the semiconductorchip, the die pad is made considerably larger than the semiconductorchip to be bonded thereto, which causes the problems described below.

In bonding the semiconductor chip to the die pad, it is necessary tobond the semiconductor chip at or near the center of the die pad.However, when the die bonding material applied to the die pad is melted,the semiconductor chip is floated on the melted die bonding material,and the die bonding material spreads largely to all sides over the uppersurface of the die pad. Therefore, in accordance with the spreading ofthe die bonding material to all sides, the semiconductor chip in thefloated state moves along the upper surface of the die pad to be awayfrom the center. Thus, when the die bonding material is hardenedthereafter, the semiconductor chip is fixed to the die pad at a positionoffset from the center. Moreover, when the semiconductor chip is put onthe die pad at an offset position, the semiconductor chip is fixed atthe offset position of the die pad without correction.

Moreover, in bonding the semiconductor chip to the die pad, it isnecessary to arrange the semiconductor chip so that each of the cornersof the semiconductor chip is oriented in a predetermined direction.However, since the semiconductor chip floated on the melted die bondingmaterial can rotate freely, each of the corners cannot be oriented in apredetermined direction. Thus, the semiconductor chip is fixed with theorientation of the corners deviated.

The positional deviation from the center and deviation of the cornerorientation of the semiconductor chip may hinder the connection of ametal wire to a predetermined electrode of the semiconductor chip inelectrically connecting the semiconductor chip to the second electrodeterminal by wire bonding or may cause such a connection failure that anintermediate portion of the metal wire comes into contact with thesemiconductor chip. Further, to package the semiconductor chip with amolded portion made of a synthetic resin, the molded portion need bemade relatively large in view of the above-described two kinds ofdeviation, which leads to an increase in size and weight of thesemiconductor device.

Particularly, when the semiconductor device is an LED device using a LEDchip as a semiconductor chip, the position of the light source and thedirectionality of light emitted from the LED chip changes due to thepositional deviation from the center and deviation of the cornerorientation of the LED chip, so that variation of the directionality oflight is large.

DISCLOSURE OF THE INVENTION

An object of the present invention is to solve the problems describedabove.

According to a first aspect of the present invention, there is provideda semiconductor device comprising: an insulating substrate having anobverse surface formed with a rectangular die pad made of a metal filmand a pair of electrode terminals made of a metal film; a rectangularsemiconductor chip bonded to an obverse surface of the die pad with adie bonding material; and a molded portion made of a synthetic resin forpackaging the semiconductor chip. The rectangle of the die pad has alength and a width which are 0.50 to 1.50 times the length and the widthof the rectangle of the semiconductor chip, respectively.

By making the length and the width of the rectangle of the die pad 0.50to 1.50 times the length and the width of the rectangle of thesemiconductor chip, the following advantages are provided. When thesemiconductor is placed on the die pad, the side surfaces of thesemiconductor chip may not be in parallel with the side surfaces of thedie pad or the semiconductor chip may be offset from the center of thedie pad. Even in such a case, the surface tension of the die bondingmaterial acts simultaneously to each side of the semiconductor chip andeach side of the die pad. As a result, as will be described later indetail, by self alignment due to the surface tension, the semiconductorchip is automatically corrected so that each side of the semiconductorchip become parallel or generally parallel with a respective side of thedie pad, or each of the corners of the semiconductor chip is orientedconstantly in a predetermined direction. Further, the LED chip isautomatically corrected to locate at or near the center of the die pad.

Thus, in bonding the semiconductor chip to the die pad on the insulatingsubstrate, by the self alignment due to the surface tension of the diebonding material, the deviation of the semiconductor chip from thecenter of the die pad can be reduced, and each of the corners of thesemiconductor chip can be oriented accurately in a predetermineddirection so that each side of the semiconductor chip become parallel orgenerally parallel with a respective side of the die pad. Therefore, themolded portion for packaging the semiconductor chip can be made smalleras compared with that of the prior art, whereby the size and weight ofthe semiconductor device can be reduced.

Particularly, in the first aspect, when the semiconductor device is achip-type LED device including an LED chip as the semiconductor chip anda light-permeable molded portion, the change of the light sourceposition and the directionality can be suppressed, whereby variation ofthe directionality can be reduced.

Further, in the first aspect, the die pad may have a side surfaceintegrally formed with a narrow extension projecting outward from thedie pad. With such an arrangement, part of the die bonding materialapplied onto the die pad spreads onto the obverse surface of the narrowextension. As a result, the thickness of the die bonding material on theobverse surface of the die pad can be reduced while the self alignmentby the die bonding material is assured. Therefore, the float height fromthe die pad, height variation and inclination of the semiconductor chipcan be reduced, and the amount of sinking of the semiconductor chip inthe die bonding material is also reduced. Thus, short-circuiting in thesemiconductor chip can be suppressed. Moreover, when the semiconductorchip is an LED chip, the reduction of the amount of light emitted fromthe LED chip can be prevented.

Further, in the first embodiment, the die pad may be formed with arecess of a size insufficient to receive the semiconductor chip. Withsuch an arrangement, part of the die bonding material applied to theobverse surface of the die pad enters the recess. As a result, thethickness of the die bonding material on the obverse surface of the diepad can be reduced while the self alignment by the die bonding materialis assured. Therefore, the float height from the die pad, heightvariation and inclination of the semiconductor chip can be reduced, andthe amount of sinking of the semiconductor chip in the die bondingmaterial is also reduced. Thus, short-circuiting in the semiconductorchip can be suppressed.

When the provision of the narrow extension is combined with theprovision of the recess, higher advantages can be obtained than whenonly either one of the above is provided.

According to a second aspect of the present invention, there is provideda semiconductor device comprising: an insulating substrate having anobverse surface formed with a die pad made of a metal film and a pair ofelectrode terminals made of a metal film; a semiconductor chip which issquare or generally square as viewed in plan and bonded to an obversesurface of the die pad with a die bonding material; and a molded portionmade of a synthetic resin for packaging the semiconductor chip. The diepad is circular as viewed in plan and has a diameter which approximatesthe diagonal dimension of the semiconductor chip, and wherein a narrowpatterned conductor made of a metal film is provided between the die padand one of the electrode terminals to integrally connect the die pad andthe electrode terminal to each other.

With such an arrangement, a thermally meltable die bonding material isapplied to the obverse surface of the die pad, and then thesemiconductor chip is placed thereon. Thereafter, the entirety is heatedto a temperature above the melting point of the die bonding material.

By the heating, the die bonding material is melted, so that thesemiconductor chip is floated on the melted die bonding material. Atthis time, the melted die bonding material spreads, while alloying, overthe entire obverse surface of the die pad and also over the bottomsurface and each of four side surfaces of the semiconductor chip. Thus,surface tension of the melted die bonding material acts between thecircumferential edge of the die pad and each of the four side surfacesof the semiconductor chip.

In this case, since the semiconductor chip is square or generally squarewhile the die pad is circular with a diameter which approximates thediagonal dimension of the semiconductor chip, the semiconductor chipfloating on the melted die bonding material undergoes self alignment formoving the LED chip to a position where the surface tension acts equallyonto each of the four side surfaces of the semiconductor chip.Therefore, even when the semiconductor is placed at a position offsetfrom the center of the die pad, the position is automatically correctedby self alignment due to the surface tension for the four sides so thatthe semiconductor chip is located at or near the center of the die pad.

Further, part of the melted die bonding material spreads also toward thenarrow patterned conductor made of a metal film and connecting the diepad to one of the electrode terminals. Therefore, a bulged portionprojecting on to the narrow patterned conductor is formed at the outercircumference of the molten solder paste, and surface tension acts alsobetween the side surfaces of the semiconductor chip and the bulgedportion spreading onto the narrow patterned conductor. Therefore, by theself alignment due to the behavior of the solder paste to make thesurface tension act equally onto each of the side surfaces, thesemiconductor chip floating on the melted die bonding material isautomatically corrected so that one of the four corners of semiconductorchip is oriented toward the narrow patterned conductor.

In this way, the semiconductor chip is automatically corrected (selfalignment) to locate at or near the center of the die pad, and at thesame time, automatically corrected (self alignment) so that one of thefour corners of the semiconductor chip is oriented toward the narrowpatterned conductor.

By the subsequent hardening of the melted die bonding material bycooling, the semiconductor chip is bonded at or near the center of thedie pad connected to one of the electrode terminals, with one of thecorners of the semiconductor chip oriented toward the narrow patternedconductor connected to the die pad so that each of the corners isconstantly oriented in a predetermined direction. Therefore, it ispossible to reduce the positional deviation of the semiconductor chipfrom the center of the die pad and the deviation of the cornerorientation of the semiconductor chip.

As a result, the possibility of a connection failure, which may occur inelectrically connecting the semiconductor chip to one of the electrodeterminals by wire bonding using a metal wire, is reliably reduced.Further, when the semiconductor chip is to be packaged with a moldedportion made of a synthetic resin, the molded portion can be madesmaller by as much as the above two kinds of deviation is reduced,whereby the size and weight of the semiconductor device can be reduced.

As noted above, the self alignment to locate the semiconductor chip ator near the center of the die pad and to orient the semiconductor chipso that one of the corners is oriented toward the narrow patternedconductor can be reliably achieved by making the diameter of the die pad0.6 to 1.5 times the diagonal dimension of the semiconductor chip.

In the second aspect, the die pad may be arranged between the pairedelectrode terminals arranged on a generally straight line, and thenarrow patterned conductor may be arranged to extend from thecircumference of the die pad at a position deviating by 45 degrees fromthe line of the electrode terminals. With such an arrangement, when thedie bonding material is melted, one of the corners of the semiconductorchip is oriented toward the patterned conductor at the 45 degreeposition. Therefore, the semiconductor chip can be bonded so that, amongthe four sides of the semiconductor chip, a pair of opposite sidesextend parallel or generally parallel with the line of the electrodeterminals while the other pair of opposite sides extend perpendicularlyor generally perpendicularly to the line of the electrode terminals.Therefore, the width and the length of the semiconductor device can bemade smaller than when the four sides of the semiconductor chip areinclined relative to the line of the electrode terminals. Accordingly,the size and weight of the semiconductor device can be advantageouslyreduced.

In the second aspect again, when the semiconductor device is a chip-typeLED device including an LED chip as the semiconductor chip and alight-permeable molded portion, the change of the light source positionand the directionality can be suppressed, whereby the variation of thedirectionality can be reduced.

In the second aspect again, the die pad may be formed with a recess of asize insufficient to receive the semiconductor chip, similarly to thefirst aspect. With such an arrangement, the variation of the floatheight of the semiconductor chip from the die pad as well as theinclination of the semiconductor chip can be reduced, andshort-circuiting in the semiconductor chip can be suppressed.

According to a third aspect of the present invention, there is provideda semiconductor device comprising: a die pad made of a metal plate and apair of electrode terminals made of a metal plate; a semiconductor chipwhich is square or generally square as viewed in plan and bonded to thedie pad with a die bonding material; and a molded portion made of asynthetic resin for packaging the semiconductor chip. The die pad iscircular as viewed in plan and has a diameter which approximates thediagonal dimension of the semiconductor chip, and a narrow patternedconductor made of a metal plate is provided between the die pad and oneof the electrode terminals to integrally connect the die pad and theelectrode terminal to each other. With such an arrangement, asemiconductor device which does not utilize an insulating substrate bututilizes a metal plate is provided.

Similarly to the second aspect, the following arrangements are alsoapplicable to the third aspect:

-   i) to make the diameter of the die pad 0.6 to 1.5 times the diagonal    dimension of the semiconductor chip;-   ii) to arrange the die pad between the paired electrode terminals    arranged on a generally straight line and to arrange the narrow    patterned conductor so as to extend from the circumference of the    die pad at a position deviating by 45 degrees from the line of the    electrode terminals; and-   iii) to make the semiconductor device a chip-type LED device    including an LED chip as the semiconductor chip and a    light-permeable molded portion.

Other objects, features and advantages of the present invention willbecome clearer from the description of the embodiments given below withreference to accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view showing a chip-type LED deviceaccording to a first embodiment.

FIG. 2 is a plan view of FIG. 1.

FIG. 3 is a perspective view showing the chip-type LED device accordingto the first embodiment.

FIG. 4 is an exploded perspective view of the first embodiment.

FIG. 5 is a sectional view taken along lines V-V in FIG. 4.

FIG. 6 is a longitudinal sectional view showing an LED chip bonded to aninsulating substrate in the first embodiment.

FIG. 7 is a plan view of FIG. 6.

FIG. 8 is a perspective view showing a first variation of the firstembodiment.

FIG. 9 is a perspective view showing a second variation of the firstembodiment.

FIG. 10 is a perspective view showing a third variation of the firstembodiment.

FIG. 11 is a perspective view showing a fourth variation of the firstembodiment.

FIG. 12 is a sectional view taken along lines XII-XII in FIG. 11.

FIG. 13 is a longitudinal sectional view showing a chip-type LED deviceaccording to a second embodiment.

FIG. 14 is a plan view of FIG. 13.

FIG. 15 is an exploded perspective view showing the chip-type LED deviceaccording to the second embodiment.

FIG. 16 is a sectional view taken along lines XVI-XVI in FIG. 15.

FIG. 17 is enlarged view showing the principal portion of FIG. 14.

FIG. 18 is a sectional view taken along lines XVIII-XVIII in FIG. 17.

FIG. 19 is a sectional view taken along lines XIX-XIX in FIG. 17.

FIG. 20 is a plan view showing a variation of the second embodiment.

FIG. 21 is an exploded perspective showing a chip-type LED deviceaccording to a third embodiment.

FIG. 22 is a plan view of FIG. 21.

FIG. 23 is a longitudinal sectional view showing a variation of thethird embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-7 show a first embodiment of the present invention.

Indicated by the reference sign 1 in these figures is a chip-type LEDdevice as an embodiment of semiconductor device.

The chip-type LED device 1 includes an insulating substrate 2 in theform of a chip. The insulating substrate 2 has an upper surface formedwith a rectangular die pad 3 and a pair of terminal electrodes 4, 5 allof which are made of a metal film, and a narrow patterned conductor 6made of a metal film and electrically connecting the terminal electrode4 to the die pad 3.

The chip-type LED device 1 further includes an LED chip 7 bonded to theupper surface of the die pad 3, a thin metal wire 8 connecting the LEDchip 7 and the terminal electrode 5 by wire bonding, and a moldedportion 9 made of a light-permeable synthetic resin such as atransparent resin for packaging the LED chip 6 and the wiring pattern 6.

The paired terminal electrodes 4, 5 extend from the upper surface ontoan end surface and a lower surface of the insulating substrate 2.

The bonding of the LED chip 7 onto the die pad 3 on the insulatingsubstrate 2 is performed as follows.

To mount the LED chip 7 which is a typical rectangular one having alength L0 and a width W0, the length L1 and the width W1 of the die pad3 are made equal or generally equal to the length L0 and the width W0 ofthe LED chip 7 so that the die pad becomes congruent or generallycongruent to the LED chip 7. In bonding, an appropriate amount of solderpaste H is applied to the upper surface of the die pad 3, as shown inFIG. 3. Then, as shown in FIG. 4, the LED chip 7 is placed on the solderpaste H. Thereafter, the solder paste in this state is heated to atemperature above the melting point of the solder and then cooled forhardening.

As indicated by double-dashed lines in FIG. 5, when the rectangular LEDchip 7 is placed on the rectangular die pad 3, the side surfaces of theLED chip 7 may not be in parallel with the side surfaces of the die pad3 or the LED chip 7 may be offset from the center of the die pad 3. Evenin such a case, with the above arrangement, the surface tension of themolten solder acts simultaneously to each side surface of the LED chip 7and each side surface of the die pad 3. As a result, by self alignmentdue to the surface tension, the orientation of the LED chip 7 isautomatically corrected so that each side of the LED chip 7 becomeparallel or generally parallel with a respective side of the die pad 3,and the position of the LED chip 7 is automatically corrected so thatthe LED chip 7 is accurately located at the center of the die pad 3.

By the hardening of the molten solder, the LED chip 7 is fixed with theposition corrected as described above.

Through the experiment by the inventors, it has been found that theautomatic correction by the self alignment due to the surface tension ofthe molten solder is reliably achieved when the length L1 and the widthW1 of the rectangle of the die pad 3 are 0.50 to 1.50 times the lengthL0 and the width W0 of the rectangle of the LED chip 7, preferably 0.65to 1.35 times, and most preferably 0.75 to 1.25 times. This holds truefor bonding materials other than solder paste such as conductive paste.

In this way, in die-bonding the LED chip 7 to the die pad 3 on theinsulating substrate 2, the self alignment by the die bonding materialreduces the positional deviation of the LED chip 7 from the center ofthe die pad 3 while making each side surface of the LED chip 7 parallelor generally parallel with a respective side surface of the die pad 3.Therefore, the width of the insulating substrate and the molded portion9 for packaging the LED chip 7 can be reduced as compared with that ofthe prior art device, whereby the size and weight of the chip-type LEDdevice 1 can be reduced. Further, the variation of directionality oflight emitted from the LED chip 6 can be reduced.

In the first embodiment, the patterned conductor 6 for electricallyconnecting the die pad 3 to the first terminal electrode 4 does notextend straight as indicated by double-dashed lines in FIG. 2 butextends obliquely as indicated by the solid lines in FIG. 2, whereby thepatterned conductor 6 is made relatively long. With such an arrangement,the contact area between the patterned conductor and the molded portion9 packaging the patterned conductor can be increased, whereby moisturein the atmosphere, for example, is reliably prevented from enteringthrough the patterned conductor 6.

The number of the patterned conductor is not limited to one. As shown inFIG. 7, two patterned conductors, i.e. the patterned conductor 6indicated by solid lines and a patterned conductor 6 a indicated bydouble-dashed lines may be provided.

FIG. 8 shows a first variation of the first embodiment.

In the first variation, each corner of the rectangular die pad 3 formedon the upper surface of the insulating substrate 2 is integrally formedwith a narrow extension 3 a which extends outward from the die pad 3.

With this arrangement, when the solder paste H is applied onto the diepad 3 and melted, part of the molten solder spreads onto the obversesurface of the narrow extension 3 a extending continuously outward fromthe die pad 3. Therefore, the thickness of the molten solder on theobverse surface of the die pad 3 can be reduced while the self alignmentdue to the surface tension of the molten solder is assured.

As a second variation of the first embodiment, the narrow extension 3 amay be provided at each side surface of the die pad 3, as shown in FIG.9. As a third variation of the first embodiment, a plurality of narrowextensions 3 a may be provided at one side surface of the pad 3 so thatthe extensions also serve as the patterned conductor 6, as shown in FIG.10. In these variations again, the thickness of the molten solder on theobverse surface of the die pad 3 can be reduced while the self alignmentdue to the surface tension of the molten solder is assured.

FIGS. 11 and 12 show a fourth variation of the first embodiment.

In the fourth variation, the rectangular die pad 3 formed on the uppersurface of the insulating substrate 2 is formed with a recess 3 b of asize insufficient to receive the LED chip 7.

With such an arrangement, when the solder paste H applied to the obversesurface of the die pad 3 is melted with the LED chip 7 placed thereon,part of the molten solder is received in the recess 3 b. Therefore, thethickness of the molten solder on the obverse surface of the die pad 3can be reduced while the self alignment due to the surface tension ofthe molten solder is assured.

FIGS. 13-19 show a second embodiment of the present invention.

Indicated by the reference sign 11 in these figures is a chip-type LEDdevice. The chip-type LED device 11 includes an insulating substrate 12in the form of a chip. The insulating substrate 12 has an upper surfaceformed with a die pad 13 made of a metal film to have a circularconfiguration with a diameter D, and a pair of terminal electrodes 14and 15 made of a metal film and provided on opposite sides of the diepad. The upper surface of the insulating substrate 12 is further formedwith a narrow patterned conductor 16 made of a metal film andelectrically connecting the terminal electrode 14 to the die pad 13.

The chip-type LED device 11 further includes an LED chip 17 bonded tothe upper surface of the die pad 13, a thin metal wire 18 connecting anelectrode on the upper surface of the LED chip 17 to the terminalelectrode 15 by wire bonding, and a molded portion 19 made of alight-permeable synthetic resin such as a transparent resin forpackaging the LED chip 17, the narrow patterned conductor 16 and themetal wire 18 on the upper surface of the insulating substrate 12. Asviewed in plan, the LED chip 17 is square or generally square with sidelength B.

The terminal electrodes 14, 15 extend from the upper surface onto an endsurface and a lower surface of the insulating substrate 12.

To bond the LED chip 17 onto the die pad 13 on the insulating substrate12, the diameter D of the die pad 13 is made close to the diagonaldimension S of the square or generally square LED chip 7.

In die bonding, an appropriate amount of solder paste H is applied tothe upper surface of the die pad 13, and then the LED chip 7 is placedon the solder paste H, as shown in FIGS. 15 and 16.

In placing the LED chip 17, it is only necessary to put the LED chip onthe solder paste H, and it is unnecessary to accurately position the LEDchip at the center of the die pad 13 or orient each corner of the LEDchip 17 in a predetermined direction.

Thereafter, the entirety is heated to a temperature above the meltingpoint of the solder to melt the solder paste H and then cooled to normaltemperature for hardening the paste.

By the heating and melting of the solder paste H, the LED chip 17 isfloated on the molten solder paste H. At this time, the molten solderpaste H spreads, while alloying, over the entire obverse surface of thedie pad 13 and also over the bottom surface and each of four sidesurfaces of the LED chip 17. Thus, surface tension of the molten solderpaste H acts between the circumferential edge of the die pad 13 and eachof the four side surface of the LED chip 17.

In this case, since the LED chip 17 is square or generally square whilethe die pad 13 is circular with a diameter D which approximates thediagonal dimension S of the LED chip 17, the LED chip 17 floating on themolten solder paste H undergoes self alignment for moving the LED chipto a position where the surface tension acts equally to each of the fourside surfaces of the LED chip. Therefore, even when the LED chip 17 isplaced at a position offset from the center of the die pad 13, theposition is automatically corrected by self alignment so that the LEDchip is located at or near the center of the die pad 13.

Further, as shown in FIGS. 17 and 18, part of the molten solder paste Hspreads also toward the narrow patterned conductor 16 connecting the diepad 13 to the electrode terminal 14. Therefore, a bulged portion hprojecting onto the narrow patterned conductor 16 is formed at the outercircumference of the molten solder paste H, and surface tension of thesolder paste H acts also between the side surfaces of the LED chip 17and the bulged portion h spreading onto the narrow patterned conductor16. Therefore, by the self alignment due to the behavior of the solderpaste to make the surface tension act equally onto each of the sidesurfaces, the orientation of the LED chip 17 floating on the moltensolder paste H is automatically corrected so that one of the fourcorners of the LED chip 17 is oriented toward the narrow patternedconductor 16.

In this way, as shown in FIGS. 17, 18 and 19, automatic correction isperformed so that the LED chip 7 is positioned at or near the center ofdie pad 13 and one of the four corners of the LED chip is orientedtoward the narrow patterned conductor 16.

By the subsequent hardening of the solder paste H by cooling, the LEDchip 17 is bonded at or near the center of the die pad 13 connected tothe electrode terminal 14, with one of the corners of the LED chip 17oriented toward the narrow patterned conductor 16 connected to the diepad 13 so that each of the corners is constantly oriented in apredetermined direction.

Through the experiment by the inventors, it has been found that the selfalignment due to the surface tension of the molten solder is reliablyachieved when the diameter D of the die pad 13 is 0.6 (lower limit) to1.5 (upper limit) times the diagonal dimension S of the LED chip 17, andis more reliably achieved when 0.8 (lower limit) to 1.2 (upper limit)times.

Therefore, “a diameter close to a diagonal dimension of thesemiconductor chip” as set forth in the claims of the present inventionmeans the above-described range.

FIG. 20 shows a variation of the second embodiment.

In the chip-type LED device 11′ of this variation, the die pad 13′ isarranged, as viewed in plan, on a center line C connecting the electrodeterminals 14′, 15′ provided at opposite ends of the insulating substrate12′ to each other. Specifically, as viewed in plan, the terminalelectrode 14′ and the terminal electrode 15′ are arranged on a straightline with the die pad 13′ interposed therebetween, and the narrowpatterned conductor 16′ connecting the die pad 13′ to the electrodeterminal 14′ is arranged to extend from the circumference of the die pad13 at a position deviating by an angle θ (=45 degrees) from the centerline C connecting the electrode terminals 14′ and 15′ to each other,i.e. from the line of the electrodes 14′, 15′. Similarly to theforegoing embodiments, an LED chip 17′ is bonded on the upper surface ofthe die pad 13′ with solder paste H, and an electrode on the LED chip17′ is connected to the electrode terminal 15′ by wire bonding using ametal wire 18′. The LED chip 17′, the narrow patterned conductor 16′ andthe metal wire 18′ on the upper surface of the insulating substrate 12′are packaged with a molded portion 19′ made of a transparent syntheticresin.

With such an arrangement, when solder paste H applied to the uppersurface of the die pad 13′ is melted with the LED chip 17′ placedthereon, self alignment due to the surface tension of the solder paste Hoccurs so that the LED chip 17′ is automatically located at or near thecenter of the die pad 13′, while, at the same time, one of the cornersis automatically oriented toward the narrow patterned conductor 16′. Asshown in FIG. 20, by subsequently fixing the LED chip in this state, theLED chip 17′ can be bonded so that, among the four sides of the LEDchip, a pair of opposite sides extend parallel or generally parallelwith the center line C connecting the electrode terminals 14′ and 15′ toeach other, i.e. with the line of the electrode terminals 14′, 15′ whilethe other pair of opposite sides extend perpendicularly or generallyperpendicularly to the center line C connecting the electrode terminals14′ and 15′ to each other. Therefore, the width F and the length E ofthe chip-type LED device 11′ can be made smaller than in the structureshown in FIG. 14 in which the four sides of the LED chip are inclinedrelative to the line of the electrode terminals 14′ and 15′.

FIGS. 21 and 22 show a third embodiment of the present invention.

In the chip-type LED device 21 according to the third embodiment,instead of the paired electrode terminals and the die pad all of whichcomprise a metal film formed on an insulating substrate, a pair ofelectrode terminals and a die pad all of which comprise a relativelythick metal plate are provided, and the insulating substrate is notused.

Specifically, both of the electrode terminal 25 and the electrodeterminal 24 connected to the circular die pad 23 via a narrow patternedconductor 26 are made of a metal plate. Similarly to the foregoingembodiments, an LED chip 27 is bonded on the upper surface of the diepad 23 with solder paste H, and an electrode on the LED chip 27 isconnected to the electrode terminal 25 by wire bonding using a metalwire 28. The LED chip 27, the narrow patterned conductor 26 and themetal wire 28 are packaged with a molded portion 29 made of alight-permeable synthetic resin such as a transparent resin.

With such an arrangement, a chip-type LED 21 which does not include aninsulating substrate can be formed by using a metal plate.

As shown in FIG. 23, in a variation of the third embodiment, theelectrode terminal 25 may be elongated for direct connection to the LEDchip 27 instead of the connection to the LED chip 27 by wire bondingusing a metal wire 28, whereby the wire bonding using a metal wire canbe eliminated.

In the third embodiment again, it is preferable that the diameter D ofthe die pad 23 is 0.6 (lower limit) to 1.5 (upper limit) times thediagonal dimension of the LED chip 27, and more preferably, 0.8 (lowerlimit) to 1.2 (upper limit) times the diagonal dimension of the LEDchip. Further, in the third embodiment again, similarly to the variationof the second embodiment shown in FIG. 20, the narrow patternedconductor 26 may be arranged to extend from the circumference of the diepad 23 at a position deviating by an angle θ (=45 degrees) from thecenter line connecting the electrode terminals 24 and 25 to each other,i.e. from the line of the electrodes 24, 25. In this case, the width andlength of the chip-type LED device 21 can be shortened for sizereduction.

In the foregoing embodiments, a chip-type LED device using an LED chipis described as an example of semiconductor device. However, the presentinvention is not limited thereto and is also applicable to such asemiconductor device as a transistor in which more than two electrodeterminals are connected to a single semiconductor chip, as well as to adiode having a structure similar to that of the chip-type LED device.

1. A semiconductor device comprising: an insulating substrate having anobverse surface formed with a rectangular die pad made of a metal filmand a pair of electrode terminals made of a metal film; a rectangularsemiconductor chip bonded to an obverse surface of the die pad with adie bonding material; and a molded portion made of a synthetic resin forpackaging the semiconductor chip; wherein a narrow patterned conductormade of a metal film is provided between the die pad and one of theelectrode terminals to integrally connect the die pad and the electrodeterminal to each other, the rectangle of the die pad having a length anda width which are 0.50 to 1.50 times a length and a width of therectangle of the semiconductor chip, respectively; and wherein thesemiconductor chip comprises an LED chip, the molded portion beinglight-permeable.
 2. The semiconductor device according to claim 1,wherein the die pad has a side surface integrally formed with a narrowextension projecting outward from the die pad.
 3. The semiconductordevice according to claim 1, wherein the die pad is formed with a recessof a size insufficient to receive the semiconductor chip.
 4. Thesemiconductor device according to claim 1, wherein the die pad has aside surface integrally formed with a narrow extension projectingoutward from the die pad, and wherein the die pad is formed with arecess of a size insufficient to receive the semiconductor chip.
 5. Asemiconductor device comprising: an insulating substrate having anobverse surface formed with a die pad made of a metal film and a pair ofelectrode terminals made of a metal film; a semiconductor chip which issquare or generally square as viewed in plan and bonded to an obversesurface of the die pad with a die bonding material; and a molded portionmade of a synthetic resin for packaging the semiconductor chip; whereinthe die pad is circular as viewed in plan and has a diameter whichapproximates a diagonal dimension of the semiconductor chip, and whereina narrow patterned conductor made of a metal film is provided betweenthe die pad and one of the electrode terminals to integrally connect thedie pad and the electrode terminal to each other.
 6. The semiconductordevice according to claim 5, wherein the diameter of the die pad is 0.6to 1.5 times the diagonal dimension of the semiconductor chip.
 7. Thesemiconductor device according to claim 5, wherein the semiconductorchip comprises an LED chip, and wherein the molded portion islight-permeable.
 8. The semiconductor device according to claim 5,wherein the paired electrode terminals are arranged, as viewed in plan,on a generally straight line with the die pad interposed therebetween,the narrow patterned conductor being arranged to extend from acircumference of the die pad at a position deviating by 45 degrees fromthe line of the electrode terminals.
 9. The semiconductor deviceaccording to claim 5, wherein the semiconductor chip comprises an LEDchip, wherein the molded portion is light-permeable, and wherein thepaired electrode terminals are arranged, as viewed in plan, on agenerally straight line with the die pad interposed therebetween, thenarrow patterned conductor being arranged to extend from a circumferenceof the die pad at a position deviating by 45 degrees from the line ofthe electrode terminals.
 10. The semiconductor device according to claim5, wherein the die pad is formed with a recess of a size insufficient toreceive the semiconductor chip.
 11. A semiconductor device comprising: adie pad made of a metal plate and a pair of electrode terminals made ofa metal plate; a semiconductor chip which is square or generally squareas viewed in plan and bonded to the die pad with a die bonding material;and a molded portion made of a synthetic resin for packaging thesemiconductor chip; wherein the die pad is circular as viewed in planand has a diameter which approximates a diagonal dimension of thesemiconductor chip, and wherein a narrow patterned conductor made of ametal plate is provided between the die pad and one of the electrodeterminals to integrally connect the die pad and the electrode terminalto each other.
 12. (canceled)